Date Calculator — Days Between Dates & Upcoming Holidays

Calculate days between any two dates, find working days, see what day of the week a date falls on, and track countdowns to upcoming holidays.

Days Between Two Dates

Enter a start date and end date to calculate the total days, working days (Mon–Fri), weeks, and months between them.

Enter the start date in YYYY-MM-DD format
Enter the end date in YYYY-MM-DD format

Days Until Upcoming Holidays

Live countdowns to major holidays — updated automatically based on today's date.

Computing holiday countdowns…

What Day of the Week?

Enter any date to see which day of the week it falls on and whether it is a weekday, weekend, or public holiday.

How to Calculate Days Between Dates

Calculating the number of days between two dates is one of the most common date-related tasks — useful for counting down to a vacation, tracking project deadlines, calculating loan terms, or figuring out how many working days are in a period. The date calculator on this page does all of this automatically, but here is how the math works:

To find the total number of days between two dates, convert each date to its Julian Day Number (a sequential integer count of days since a fixed epoch), then subtract the earlier from the later. Modern programming languages and spreadsheets do this internally whenever you subtract one date from another — for example, in Excel or Google Sheets, entering =B1-A1 where both cells are formatted as dates will return the number of days between them.

For working days (also called business days), the calculation requires counting only Monday through Friday. The standard approach is to count total weeks in the range (each contributing 5 working days), then add the remaining days while skipping weekends. If you also need to exclude public holidays, you must additionally subtract any holidays that fall on weekdays within the date range — which is exactly what this calculator does when connected to the HolidaySync public holiday data.

For weeks, divide total days by 7 (rounding down for complete weeks). For approximate months, divide by 30.44 (the average number of days in a calendar month). For exact calendar months, count from the start date to the same day-of-month in each subsequent month — a more complex calculation handled automatically by this tool.

Frequently Asked Questions

How many days until Christmas?
Christmas falls on December 25 every year. The "Days Until Upcoming Holidays" section above shows a live countdown updated to today's date. The count resets on December 26 to begin counting towards next year's Christmas.
How do I calculate working days between two dates?
Working days (also called business days) are Monday through Friday, excluding weekends. Use the Days Between Two Dates tool above — it automatically shows total days, working days, full weeks, and approximate months. Simply select your start and end dates and click Calculate.
What day of the week is a specific date?
Use the "What Day of the Week?" tool above. Enter any date — past, present, or future — and the calculator instantly shows the day of the week (Monday through Sunday), whether it is a weekday or weekend, and attempts to identify it as a public holiday in your region.
How many weeks until a holiday?
The holiday countdown cards above show both total days and implicitly allow you to calculate weeks by dividing by 7. For a precise week count between any two dates, use the Days Between Two Dates tool — the result includes a "Complete Weeks" figure in the breakdown.